How do you decide which is the subject, indirect object, and direct object in a sentence?

Question

From your videos I understand that the direct object is a noun that receives the action of a verb, an indirect object is the recipient of a direct object. But if there is not any direct object, then how do you decide what the indirect object is. I was doing some practise of direct and indirect object pronouns and couldn't understand how the translation of some sentences were made. For example:

1: He is interested in the movie Se interesa en la pelicular. Se la interesa.

2: Mary's head hurts A María le duele la cabeza. Se la duele.

Thank You

Answer 1

Both interesar and doler are gustar-like verbs. They form intransitive sentences which have no direct object.

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¿A qué, quién o quiénes afecta el verbo principal?

He is interested in the movie. = El está interasado en la película. The movie is interesting to him.

¿Qué le interesa? La película

Objeto Directo? = La película.

La película is the subject of this intransitive sentence (no. d.o.) le is the i.o.p., a él would be the optional i.o.

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¿Qué le duela a María? La cabeza.

Objeto Directo = La cabeza. Her head is painful to her.

La cabeza is the subject of this intransitive sentence...there is no direct object. le, a Maria is the i.o.p. and i.o.

Was this the answer given in the lesson?

2: Mary's head hurts A María le duele la cabeza. Se la duele

Se la duele looks incorrect to me. You cannot use the la (d.o.p.) to substitute for the subject, la cabeza. (ella would be the proper pronoun for a feminine "it" subject) A María le duele la cabeza.

Same argurment with 1: He is interested in the movie Se interesa en la pelicular. Se la interesa. This looks incorrect to me. A él le interesa la película. The d.o.p. (la) cannot substitue for the subject of the sentence.

Wait for comments.

Yes this was the answer given in he lesson - r2rsom, Dec 8, 2011

Answer 2

Hello r2rsom:

Para identificar el objeto directo recuerda esto:

¿A qué, quién o quiénes afecta el verbo principal?

1. He is interested in the movie. = El está interasado en la película.

¿Qué le interesa? La película

Objeto Directo = La película.

1. Mary's head hurts = A María le duele la cabeza.

¿Qué le duela a María? La cabeza.

Objeto Directo = La cabeza.

Saludos.

English analysis does not always work for Spanish grammar. - 0074b507, Dec 6, 2011

This answer seems to contrast with the answer of qfreed. i am still confused - r2rsom, Dec 7, 2011